Full Idea
Whereas reason is a universal instrument which can serve on any kind of occasion, the organs of a machine need a disposition for each action; so it is impossible to have enough different organs in a machine to respond to all the occurrences of life.
Gist of Idea
Reason is universal in its responses, but a physical machine is constrained by its organs
Source
René Descartes (A Discourse on Method [1637], §5.57)
Book Reference
Descartes,René: 'Discourse on Method/The Meditations', ed/tr. Sutcliffe,F.E. [Penguin 1968], p.74
A Reaction
How can Descartes know that reason is 'universal' rather than just 'very extensive'? Is there any information which cannot be encoded in a computer? It doesn't feel as if there any intrinsic restrictions to reason, but note Idea 4688.
Related Idea
Idea 4688 We imagine small and large objects scaled to the same size, suggesting a fixed capacity for imagination [Lavers]